The present invention relates to a method of forming a a multi-color image and materials for forming multi-color image to be used therefor. In more detail, it relates to a method of forming a multi-color image in the color-proof for color-proofing used for the proofing operation during printing and plate-making processes.
In the color printing, a material called color-proof for color-proofing is commonly used in order to check the color after finishing printing, the reproduction of tone, etc, in various operating processes of plate-making.
This color-proof has been made so far mainly by surprint method, overlay method, transfer method, etc. depending on the form thereof.
Recently, among them, the transfer method having relatively good color-reproducibility and operativity is often used as a general-purpose method.
In most of this transfer system, however, because the surface of the ultimate image-receiving material (hereinafter, referred to as ultimate material) forming the image is covered with a layer comprising organic high-molecular substance in all cases as described in Japanese Unexamined Patent Publication No. Sho 47-41830, No. Sho 61-286857, No. Sho 61-286858, etc., the gloss of the surface of the image obtained is too high leading to a problem that it affords a different impression from the image quality on actual printing.
Also, for the purpose of adjusting the gloss on the surface of the image, a method is used of changing the surface gloss of the image, wherein a matted sheet, the surface thereof being coarsened, and the surface of the image formed on the ultimate material are superposed and then treatments such as pressurizing and heating are performed. But, it has a problem in operativity in such ways that the operation of this method itself is troublesome, many kinds of matted sheets are required for obtaining the aimed gloss, and others.
Next, in a method, wherein a transferable colored image is transferred onto an intermediate image-receiving sheet (hereinafter, referred to as an intermediate sheet) and then it is transferred onto a permanent supporter, as described in Japanese Unexamined Patent Publication No. Sho 61-189535, when transferring onto the permanent supporter such as paper under heat and pressure after the colored image transferable onto the intermediate sheet material comprising a first layer and a second layer has been transferred onto the intermediate sheet, there are advantages that said layers are embedded corresponding to irregularities of paper to facilitate the close contact with paper and a matting process is not required on releasing. However, because the non-image area is covered with a layer comprising organic high-molecular substance, the finish becomes different from the actual printed matter after all.
Moreover, in Japanese Unexamined Patent Publication No. Hei 3-21955 a method is disclosed, wherein an ionomer resin is contained in the image-receiving layer of the intermediate sheet, and the image alone is temporarily transferred thereonto under pressure and heat. Then as a next process, an ultimate material such as paper is superposed on the surface of the image formed on the intermediate sheet, and finally the image area alone is transferred onto the ultimate material under pressure and heat to make a proof. This method surely allows the image area alone to be transferred onto the ultimate material, thus the finish is close to the printed matter. The image layer used therefor however comprises a colored photosensitive resin layer and a heat-adhesive release layer in order to increase the adhesive force between image layers when the image layers are superposed one on another upon transferring. Due to the interposition of release layers between colored photosensitive resin layers of respective colors, optical dot gains are caused in the final image layer on the ultimate material resulting in a different tone from the actual printed matter.
In view of the problems as described above, the invention aims at that, by finally transferring the real image of the image layer alone on the supporter onto the ultimate material and by forming the image layer with a colored photosensitive layer alone without providing the heat-adhesive layer in that image layer, the surface of the non-image area on the ultimate material is exposed, thus achieving the image quality quite close to that of a print formed with inks alone in the reproducibility of the image area.